Thread: Failed CT emissions test

Hi Everyone- I tried to get the 1991 SCC project sentra se-r to pass the emissions test today. Unfortunately, I didn't have any luck getting through. Here are the numbers:

HC- reading 38 ppm limit 150 pmm - pass
CO- reading .01% limit .8% - pass
NOx- reading 2512 liimit 1750 - fail

I had a new magnaflow cat installed before the test and the car was plenty warm. I was hoping the new cat would help push things in the right direction.

Does anyone have some recommendations on how to get the NOx down? The rest of the numbers seems good and well below the limit.

Thanks in advance- Cory

You did better then me I passed the gas cap only fuck ct

take timing out

I thought you guys were emissions exempt after the car is 20 years old?

Clean your EGR, ensure you have proper fuel pressure, change fuel filter, ensure proper cooling system. Can been caused by lean, EGR, carbon, overheating or even a cat but you say yours is new

this.

I just need the car to pass the test one more time! I am going to head up to see Jimmi in Canton and see if we can get the car to pass. The car has the stock ECU in it, but I am not sure where it is currently timed at.

can take timing out by moving the dizzy just make sure you mark where it is now

Pics of car???? would love to see it after all these years. I remember reading those articles all the time

NOx is the result of high combustion temperatures, so as stated above by the others:
improve or restore EGR operation (won't effect NOx at idle, if measured)
Retard ign timing (try -2deg from spec)